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Leopard and Universal Binary

yadmonkey

yadmonkey

macrumors 65816
Original poster
Aug 13, 2002
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Western Spiral
My understanding is that the reason for Leopard being so large (9GB free space required for install) is that it contains instruction sets for both Intel and PPC Macs (universal binary). My question is this - does that mean I could make an external drive which could boot both PPC and Intel Macs?

In case you are wondering why I ask, it's because I use an external drive in order to service my Macs - run Disk Warrior, Tech Tool, etc. It'd be really cool to have one drive which boots both types of Mac.
 
yadmonkey said:
My understanding is that the reason for Leopard being so large (9GB free space required for install) is that it contains instruction sets for both Intel and PPC Macs (universal binary). My question is this - does that mean I could make an external drive which could boot both PPC and Intel Macs?

In case you are wondering why I ask, it's because I use an external drive in order to service my Macs - run Disk Warrior, Tech Tool, etc. It'd be really cool to have one drive which boots both types of Mac.
Click to expand...

My understanding is that it installs the version for your specific processor. So no the OS does not work off the universal binary system. Feel free to prove me wrong once it is released though :).
 
Partition The External Then Install Leopard On Each Half From Each Type Mac

yadmonkey said:
My understanding is that the reason for Leopard being so large (9GB free space required for install) is that it contains instruction sets for both Intel and PPC Macs (universal binary). My question is this - does that mean I could make an external drive which could boot both PPC and Intel Macs?

In case you are wondering why I ask, it's because I use an external drive in order to service my Macs - run Disk Warrior, Tech Tool, etc. It'd be really cool to have one drive which boots both types of Mac.
Click to expand...
Yes by partitioning the external into two parts and installing Leopard on each half from each type of Mac. Then you can build your service software on each version of OS X while hooked to each type of Mac from that partition.

I know you meant ONE install. No that is not possible. But my solution still keeps it all on one drive.
 
My thanks to you all - very useful info. I'll give the partitioning a try.

BTW, now that you can boot to a USB drive on Intel Macs, would it be possible to install a stripped-down OS onto a thumb drive and use that for a service drive for Intel Macs?
 
Multimedia said:
I know you meant ONE install. No that is not possible.
Click to expand...

Actually, yes it is possible.

I installed Leopard on an external drive attached to a iBook G4 this afternoon, (drive was formatted using the APM, Apple Partition Map, scheme) then connected the drive to an Intel Mac Mini and was able to boot it just fine. (choosing the external FW drive via either the Option-key bootpicker at startup or from Startup Disk in System Preferences.)

Not sure if the reverse is true, i.e. if you were to install on an Intel Mac (assuming you used Apple Partition Map for the drive, not GUID... this is key) whether it would install all of the PPC code. (haven't tried yet, however I'd assume so as the sizes of installed OSes are very similar)

I can't tell you how much of a Godsend this is for those of us who have to support both PPC and x86 Macs. Up to now I've kept 2 partitions with PPC and Intel systems, but keeping all my diagnostic and repair utilities and preferences in sync across the two systems has been a pain. Now I can just have one single OS partition to boot both PPC and x86 boxen. Yay!

(Tho' I may throw together a smaller drive with 10.4.x and 9.2.x on it for those increasingly rare occasions where I have to support much older Macs. But that's another project...)
 
iankasley said:
Actually, yes it is possible.

I installed Leopard on an external drive attached to a iBook G4 this afternoon, (drive was formatted using the APM, Apple Partition Map, scheme) then connected the drive to an Intel Mac Mini and was able to boot it just fine. (choosing the external FW drive via either the Option-key bootpicker at startup or from Startup Disk in System Preferences.

Not sure if the reverse is true, i.e. if you were to install on an Intel Mac (assuming you used Apple Partition Map for the drive, not GUID... this is key) whether it would install all of the PPC code. (haven't tried yet, however I'd assume so as the sizes of installed OSes are very similar)

I can't tell you how much of a Godsend this is for those of us who have to support both PPC and x86 Macs. Up to now I've kept 2 partitions with PPC and Intel systems, but keeping all my diagnostic and repair utilities and preferences in sync across the two systems has been a pain. Now I can just have one single OS partition to boot both PPC and x86 boxen. Yay!

(Tho' I may throw together a smaller drive with 10.4.x and 9.2.x on it for those increasingly rare occasions where I have to support much older Macs. But that's another project...)
Click to expand...

Nicely done! When I saw how large the installs were on both my Macs (G4 and Macbook), I still wondered about this. I'm going to make a universal drive right away.

So did you format the drive using the Intel Mac? Now I'm looking forward to a Diskwarrior patch for Leopard and my service drive will be complete!
 
yadmonkey said:
So did you format the drive using the Intel Mac?
Click to expand...

No, the trick is to format the drive on the PPC-based machine (use the setting for the Apple Partition Map partitioning scheme, and *not* the GUID scheme) and then do the install on the PPC. As far as I know, the OS X installer won't allow you to install the OS onto an APM formatted drive on an Intel Mac, however it actually *can* boot from one just fine. Most (or maybe all?) PPC Macs can't boot from GUID-formatted drives, although they can mount them fine. (at least this applies to ones running 10.4.2 and later)

If you don't have access to a PPC-based Mac but still want to create a Universal Binary boot partition, you might be able to do your install on a GUID-formatted drive, then use the "Restore" function in Disk Utility to clone over the whole OS to another drive formatted as APM. (Haven't tried this yet with 10.5 but I think it should work, assuming the OS install on an Intel machine is indeed Universal Binary)

This article gives more info about the various partition table formats and such...
http://rentzsch.com/tidbits/intelbasedMacBootIncompatibility

I can't seem to find where I read it at the moment, but I seem to recall having heard somewhere that OS X (at least on Intel) can actually be booted off of a drive that uses the Windows-style Master Boot Record partitioning scheme, too. I'll try and investigate this later. Makes me wonder if I might be able to have one single drive that could boot both Macs and PCs. (I could put something like a BartPE-customized Windows partition with all my PC tools on there. And/or a stripped-down Linux installation. Could be very handy...)
 
Just verified that my Intel Mac Mini boots from a copy of 10.5 which has been cloned to an external FireWire drive which I reformatted with a Master Boot Record-type partition table. (more out of curiosity than anything, but this may have some usefulness at some point...)
 
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